JP2003013900A - Solution transfer device in constant quantity using air lift pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solution transfer device capable of transferring solution in constant quantity when transferring the solution using an air lift pump. SOLUTION: This solution transfer device using the air lift pump comprises a feed side liquid feed pipe 3 connecting a feed side solution tank 1 to an air lift separator 2, a receiver side liquid feed pipe 5 connecting a receiver side solution tank 4 to the air lift separator, a compressor 6 feeding compressed air to the feed side liquid feed pipe immersed in the solution in the feed side solution tank, and a vacuum pump 8 connected to the air lift separator. A constant quantity solution tank 10 is disposed in a midway of the receiver side liquid feed pipe on the lower side of the air lift separator, multiple overflow pipes 14 varying their installation heights at every prescribed solution amounts are provided in the height direction of the constant quantity solution tank, opening/closing valves 15 and 16 are provided in the respective overflow pipes and the lower part of the constand quantity solution tank, and the downstreams of the respective overflow pipes are connected to the feed side solution tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a solution transfer device using an air lift pump that uses both a vacuum system and a compressed air supply system, and more specifically, a quantitative solution solution using such an air lift pump. The present invention relates to a fixed-quantity solution transfer device capable of transferring.

[0002]

2. Description of the Related Art Conventionally, in a nuclear fuel reprocessing facility or the like, there is no mechanical drive unit for transferring a solution containing a nuclear fuel substance such as a uranyl nitrate solution or a plutonium nitrate solution, and therefore maintenance is extremely low. For some reasons, air lift pumps that use both a vacuum system and a compressed air supply system are widely used.

In a solution transfer device using an air lift pump of this type, as shown in FIG. 3, for example, a feed side solution tank 1 and an air lift separator 2 arranged above the feed side solution tank are provided in a feed side liquid feed pipe. 3, the receiving side solution tank 4 arranged below the air lift separator 2 and the air lift separator 2 are connected by a receiving side liquid sending pipe 5. Furthermore, the compressed air from the compressor 6 is supplied from the compressed air injecting unit 7 to the liquid feed pipe 3 on the feed side immersed in the solution in the solution tank 1 on the feed side, and the vacuum pump 8 is provided to the air lift separator 2. It is connected. In the figure, reference numeral 6a indicates a compressed air flow meter, and 8a indicates a vacuum gauge.

When the solution is transferred from the solution tank 1 on the sending side to the solution tank 4 on the receiving side by using such an apparatus, a vacuum pump 8 is used to adjust the internal pressures of the air lift separator 2 and the liquid sending pipes 3, 5. Compressed air is supplied from the compressor 6 via the compressed air injecting unit 7 to the liquid sending pipe 3 immersed in the sending side solution tank 1 while maintaining a negative pressure from the atmospheric pressure. In the feed-side liquid feed pipe 3, the solution that has risen to a certain height due to negative pressure becomes a gas-liquid mixed flow due to the supply of compressed air, and the apparent density becomes small, so that the feed-side liquid feed pipe 3 Is further raised and flows into the air lift separator 2. The gas-liquid mixed flow that has flowed in is separated into gas and liquid in the air lift separator 2, and the solution falls due to gravity and is transferred to the receiving side solution tank 4 through the receiving side liquid supply pipe 5.

[0005]

In the conventional solution transfer device using the air lift pump as shown in FIG. 3, the inflow of the gas-liquid mixed flow into the air lift separator 2 is not steady but pulsating. It has been known. Further, during the transfer of the solution, the insides of the liquid supply pipes 3 and 5 are maintained at a negative pressure than the atmospheric pressure, so that the solution retention amount in the liquid supply pipe is always present. Therefore, there is a problem that the quantitativeness of the solution transfer amount is relatively poor mainly due to these two reasons.

In view of the above problems, therefore, the present invention is also effective in transferring a solution using an air lift pump.
It is an object of the present invention to provide a new and improved solution transfer device capable of performing quantitative solution transfer.

[0007]

[Means for Solving the Problems] That is, a solution quantitative transfer device using an air lift pump of the present invention comprises a feed side liquid feed pipe connecting a feed side solution tank and an air lift separator arranged above the feed side solution tank. , Compressed air is supplied to the receiving-side solution sending pipe that connects the receiving-side solution tank arranged below the air lift separator and the air-lift separator, and the sending-side solution sending pipe immersed in the solution in the sending-side solution tank In a conventional solution transfer device using an air lift pump consisting of a compressor and a vacuum pump connected to the air cell lift separator, a solution fixed amount tank is provided in the middle of the receiving side liquid transfer pipe below the air lift separator. The overflow pipe that overflows when a certain amount of the solution has accumulated in this solution metering tank is installed at the specified height of the solution metering tank. Placed in, the overflow pipe and the solution quantitative vessel bottom to the opening and closing valve is provided, is characterized in that the downstream of the overflow pipe is connected to the feed side solution bath.

According to the apparatus of the present invention having the above-described structure, first, the original air lift pump function is used to transfer an amount of the solution not exceeding the transfer target value from the solution tank on the sending side to the solution tank on the receiving side, and then the insufficient solution is transferred. In order to replenish the amount, a fixed amount of the solution stored in the solution metering tank is quantitatively supplied to the receiving solution tank a required number of times, so that the solution can be quantitatively transferred to the receiving solution tank.

In a preferred embodiment of the present invention, a plurality of overflow pipes having different installation heights are installed in the height direction of the solution metering tank for each predetermined solution amount, and an opening / closing valve is provided in each overflow pipe. , Connect the downstream of each overflow pipe to the solution tank on the feed side.

According to the structure in which a plurality of overflow pipes are installed, the opening / closing valve provided in each overflow pipe is selected to change the overflow height, thereby selecting a fixed amount of the solution accumulated in the solution metering tank. be able to. As a result, in order to replenish the insufficient solution amount, when a fixed amount of the solution stored in the solution fixed amount tank is supplied to the receiving side solution tank a fixed number of times, it is possible to appropriately select the fixed amount of solution to be supplied in a fixed amount. , It is possible to minimize the number of times of constant supply from the solution fixed amount tank to the receiving side solution tank.

Further, in a preferred embodiment of the present invention, the downstream side of each overflow pipe is connected to one return pipe, and the return pipe is connected to the feed side solution tank. According to such a configuration, it is possible to avoid the complication caused by drawing a large number of pipes, as compared with the case where the downstream sides of the plurality of overflow pipes are respectively connected to the feed side solution tank.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 shows a preferred embodiment of a solution quantitative transfer device according to the present invention using an air lift pump, and the same members as those in the conventional device of FIG. .

The structure of the apparatus of the present invention shown in FIG. 1 is different from that of the conventional apparatus of FIG. 3 in the present invention. In the present invention, a solution metering tank 10 is provided in the middle of the receiving side liquid supply pipe 5 below the air lift separator 2. That is the point.

FIG. 2 is an enlarged detailed view of the vicinity of the solution quantification tank within the dotted line in FIG. 1. As can be seen from FIG. 2, the solution quantification tank 10 has a solution quantification section 11 therein. , An upper solution inflow pipe 12, a lower solution discharge pipe 13, and a side overflow pipe 14.

In the illustrated embodiment, the solution metering tank 10
There are four overflow pipes 14a, 14b, 14c, 14d whose installation heights are changed in the height direction for each predetermined amount of solution, and opening / closing valves 15a, 15b, 15c, 15d are provided in each overflow pipe. It is provided. Further, an opening / closing valve 16 is provided in the solution discharge pipe 13 below the solution metering tank 10.

Each overflow pipe 14a-14d is
The downstream side may be connected to the feed side solution tank 1, but in the embodiment of FIG. 1, the downstream side of each overflow pipe is connected to one return pipe 17, and the return pipe 17 is connected to the feed side solution tank 1. Connected to.

The operation of the solution quantitative transfer device in the embodiment of the present invention shown in FIGS. 1 and 2 will be described below. First, the solution (150 L) to be transferred to the receiving side solution tank 4 is put in the sending side solution tank 1 (volume 200 L), and the tip of the receiving side liquid supply pipe 5 is also put in the receiving side solution tank 4 (volume 200 L). A solution (30
L). If there is no solution in the receiving side solution tank 4 and the tip of the receiving side liquid supply pipe 5 is not blocked, when the operation of the vacuum pump 8 is started, air will flow from the receiving side liquid supply pipe 5 tip part. It will flow in, and it will be impossible to maintain a negative pressure inside the air lift separator 2 and the liquid supply pipes 3 and 5. For this reason, it is necessary to previously fill a small amount of solution into the receiving side solution tank 4 such that the tip of the receiving side liquid supply pipe 5 can be immersed.

Next, the operation of the vacuum pump 8 is started to make the pressure inside the air lift separator 2 and the liquid supply pipes 3, 5 negative compared with the atmospheric pressure. The degree of vacuum at this time is −
The suitable degree is about 0.030 MPa to -0.045 MPa, and the degree of vacuum can be adjusted by adjusting the opening degree of the degree of vacuum adjusting valve 8b. At the same time, the operation of the compressor 6 is started, and compressed air is injected from the compressed air injecting section 7 into the feed side liquid supply pipe 3. A suitable inflow rate of compressed air is about 8 NL / min to 20 NL / min.
The flow rate can be adjusted by the flow meter 6a.

By keeping the pressure inside the feed side liquid feed pipe 3 at a negative pressure from the atmospheric pressure, the amount of the solution corresponding to the degree of vacuum rises inside the feed side liquid feed pipe 3. further,
When the compressed air is fed, the solution inside the feed liquid feed pipe 3 and the air are mixed with each other to generate a gas-liquid mixed flow. Since the apparent average density of the generated gas-liquid mixed flow is smaller than that of the original solution, the gas-liquid mixed flow further rises in the feed side liquid feeding pipe 3 and flows into the air lift separator 2 to be gas-liquid separated.

The solution separated from the gas descends in the pipe due to its own weight, passes through the solution metering tank 10, and flows into the receiving solution tank 4 through the receiving liquid supply pipe 5. At this time, the opening / closing valve 16 at the bottom of the solution metering tank 10 is opened, and the solution passes through the solution metering tank 10 without being accumulated. Also,
In order to prevent the backflow to the solution tank 1 on the sending side, the opening / closing valves 15a to 15d of the overflow pipes 14a to 14d are used.
Keep all closed. When stopping the liquid supply to the receiving side solution tank 4, the vacuum pump 8 is stopped, the vacuum inside the air lift separator 2 and the liquid supply pipes 3 and 5 is opened to the atmosphere, and the inflow of compressed air is made zero. It is done by doing.

According to the above procedure, the amount of the solution that does not exceed the transfer target value (85.1 L in the case of this embodiment) is transferred from the sending side solution tank 1 to the receiving side solution tank 4 by the air lift pump.

After sending the solution by the air lift pump,
In order to replenish the difference between the transfer target value and the above-mentioned actual transfer amount (insufficient solution amount), in the apparatus of the present invention, fine adjustment by the fixed amount supply of the solution using the solution fixed amount tank 10 is performed by the following procedure. carry out. That is, the solution quantification tank 10
The lower opening / closing valve 16 is closed and the opening / closing valves 15a to 15d attached to the four overflow pipes 14a to 14d.
Only one of them (for example, 15a) is opened, and the solution is measured by the air lift pump in the same procedure as above.
Transfer to 0. The solution that has flowed into the solution metering tank 10 through the air lift separator 2 does not flow into the receiving solution tank 4 because the opening / closing valve 16 is closed, so that the solution accumulates in the solution metering tank 10 and opens and closes the opening / closing valve 15a. After having accumulated up to the height of the overflow pipe 14a, it overflows from the overflow pipe 14a and is returned to the feed side solution tank 1 by the return pipe 17. After confirming the overflow from the overflow pipe 14a, the operation of the vacuum pump 8 and the compressor 6 is stopped, and the transfer of the solution to the solution metering tank 10 is stopped. Next, after the overflow of the solution from the overflow pipe 14a is stopped, the opening / closing valve 16 at the bottom of the solution metering tank 10 is opened to quantitatively transfer a fixed amount of the solution accumulated in the solution metering tank 10 to the receiving side solution tank 4. Additional supply is possible.

In the illustrated embodiment, four overflow pipes having different installation heights are installed in the height direction of the solution metering tank 10 for each predetermined solution amount, and the overflow pipe 14a has a 1L solution amount. Overflow pipe 14
b is a 2 L solution volume, the overflow pipe 14c is a 4 L solution volume, and the overflow pipe 14d is installed at a height capable of quantitatively supplying an 8 L solution volume. These quantitative supply errors are within ± 0.005 L per batch for any solution amount.

The fixed amount supplied by the solution fixed amount tank 10 is determined from the difference between the target value and the initial transfer amount by the air lift pump (insufficient solution amount) so as to minimize the difference from the target value and the solution fixed amount. It is determined so as to minimize the number of times of constant supply from the tank 10. In this embodiment, the target value is 85.
1L and the initial transfer amount by the air lift pump was 77.9L, the difference was 7.2L,
1 L, 2 L and 4 L solution volume once, ie 3
It is sufficient to supply a fixed amount of 7 L in total by the number of times of supply.

In this embodiment, since the fixed amount supply interval by the solution fixed amount tank 10 is 1 L, a maximum difference of 0.5 L occurs when additional supply is performed using such a solution fixed amount tank. Become. Further, the supply error of the solution quantification tank 10 is 0.
Since it is 005 L / batch, the root-mean-square error is (n × (0.005) ² ) ^1/2 when the quantitative supply is performed n times. Therefore, the maximum value of the error related to the fixed amount supply is 0.
It becomes 5+ (n × (0.005) ² ) ^1/2 (liter). In the case of this embodiment, since the target value is 85.1 L and n = 3 times, the maximum value of the liquid transfer error is [0.5+ {3 × (0.005) ² } ^1/2 ] /85.1.
× 100 = 0.60%.

In the illustrated embodiment, the solution metering tank 10
Although four overflow pipes 14 are installed in the above, it is also possible to install only one. For example, when only the overflow pipe 14a of FIG. 2 is installed to make it possible to supply a fixed amount of a 1 L solution, a fixed amount of 7 times for each 1 L is supplied to replenish the total amount of the insufficient solution of 7 L. Is possible. However, in this case, the number of times of fixed quantity supply is more than three times in the above-described embodiment, so that the root mean square error may be slightly increased. From such a viewpoint, as in the illustrated embodiment, a plurality of overflow pipes are installed so that the amount of solution to be quantitatively supplied from the solution metering tank to the receiving solution tank can be appropriately selected, and the number of times of metering can be adjusted as much as possible. It is desirable to keep the number small.

Further, when a fixed amount of the solution is additionally supplied to the receiving side solution tank 4 by using the solution metering tank 10, immediately after the solution is stored in the solution metering tank 10 or the overflow pipe 14a.
Immediately after the solution overflows from one of the solutions 14d to 14d, the solution amount fluctuates because the liquid surface in the solution metering tank is wavy, and the solution quantity accumulated in the solution metering tank is not stable. Therefore, it is necessary to supply the fixed amount to the receiving-side solution tank 4 after the liquid level in the solution fixed-quantity tank disappears and the amount of the solution accumulated in the tank disappears.

In the illustrated embodiment, an ultrasonic liquid level gauge installed in the solution metering tank 10 is used as a means for confirming whether the liquid level in the solution metering tank 10 has disappeared. . That is, the sensor head 18 of the liquid level gauge is attached to the upper lid portion of the solution metering tank 10, and the sensor head 1 is detected by the ultrasonic waves generated from the sensor head 18.
The distance from 8 to the liquid surface in the solution metering tank 10 can be measured without contact. When there is no change in this distance, it is determined that the amount of solution accumulated in the tank has not changed, and the open / close valve 16 is opened to add a fixed amount of solution accumulated in the tank to the receiving side solution tank 4. By supplying the solution, the solution can be reliably supplied in a fixed amount. The displacement signal of the liquid level measured by the sensor head 18 is sent by a cable 19 to an amplifier unit (not shown) placed at a position where the operator can confirm, and the operator confirms the presence or absence of displacement to open / close the valve. 16 operations can be performed.

[0029]

As can be seen from the above description, according to the present invention, an overflow pipe with an opening / closing valve is provided in a solution transfer line of a solution transfer device using an air lift pump that uses both a vacuum system and a compressed air supply system. It is possible to quantitatively transfer the solution by arranging the provided solution quantification tank and supplying a fixed amount of the solution accumulated in the solution quantification tank to the receiving solution tank.

Further, by installing a plurality of overflow pipes having different installation heights for each predetermined amount of solution in the solution metering tank, and selecting the opening / closing valve of each overflow pipe to change the overflow height, It is possible to select a fixed amount of solution to be stored in the solution fixed amount tank, and to select the fixed amount of fixed amount of solution to be supplied to the receiving side solution tank accordingly. By minimizing, it becomes possible to perform quantitative transfer with less error.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an embodiment of a solution quantitative transfer device using an air lift pump according to the present invention.

FIG. 2 is an explanatory diagram in which a dotted line portion in FIG. 1 is enlarged.

FIG. 3 is an explanatory diagram showing an example of a conventional solution transfer device using an air lift pump.

[Explanation of symbols]

1: Sending side solution tank 2: Air lift separator 3: Delivery side liquid delivery piping 4: Recipient solution tank 5: Receiving side liquid supply piping 6: Compressor 8: Vacuum pump 10: Solution quantitative tank 14: Overflow piping 15: Open / close valve for overflow piping 16: Open / close valve at the bottom of the solution metering tank

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tsutomu Kurita             Nuclear fuel, 4-3 Muramatsu, Tokai-mura, Naka-gun, Ibaraki Prefecture             Cycle Development Organization Tokai Office F term (reference) 3H079 AA09 BB03 CC12 DD02 DD12                       DD20 DD27 DD41 DD44 DD55

Claims (3)

[Claims] 1. A feed-side liquid feed pipe connecting the feed-side solution tank and an air lift separator arranged above the feed-side solution tank, and a connection between the receiving-side solution tank arranged below the air-lift separator and the air-lift separator. An air lift including a receiving side liquid sending pipe, a compressor for supplying compressed air to the sending side liquid sending pipe immersed in the solution in the sending side solution tank, and a vacuum pump connected to the air lifter separator. In a solution transfer device using a pump, a solution metering tank is arranged in the middle of the receiving side liquid sending piping below the air lift separator, and an overflow piping overflows when a predetermined amount of the solution is accumulated in the solution metering tank. It is installed at a predetermined height of the solution metering tank, and an opening / closing valve is installed under the overflow pipe and the solution metering tank. A fixed-quantity solution transfer device using an air lift pump, characterized in that the downstream of the overflow pipe is connected to the solution tank on the feed side. 2. A plurality of overflow pipes having different installation heights are installed in the height direction of the solution metering tank for each predetermined amount of solution, an opening / closing valve is provided in each overflow pipe, and a downstream of each overflow pipe is installed. The fixed-quantity solution transfer device according to claim 1, which is connected to the solution tank on the sending side. 3. The solution quantitative transfer device according to claim 2, wherein the downstream of each overflow pipe is connected to one return pipe, and the return pipe is connected to the feed side solution tank.